Advanced Materials Research Vols. 516-517

Abstract: During the production of thermal horizontal well, recovery ratio will be reduced by the deficiency of traditional steam injection methods, which include finite effective heating range, poor level of producing reserves etc. In order to improve efficiency of steam and well yield，a new method—multipoint steam injection technology is presented in this paper, which can improve steam injection profile distribution in thermal horizontal wells. Several factors including multiphase flow, pressure drop, variable mass flow and reservoir heterogeneity, are taken into consideration in this method. By the new technology, Steam injection string used in horizontal wells is divided into several independent units through applying matching equipments. Based on the optimization of steam absorption capacity of every unit, steam injection profile distribution is improved. The validation of multipoint steam injection technology and matching equipments are verified through ground simulation tests in this paper. Moreover, the influence of steam injection parameters is also analyzed.

Abstract: Take the superheated steam system of a 330MW unit as the object, by means of the collection and research on the data of the overheating system of thermal power units and simulation tools in matlab, the results were analyzed, and then presents a construction method of the dynamic compensating function which take the load as the variable, at last, simulate and verify the constructor function.

Abstract: Non-condenable gases decrease performance of heat transfer by degrading condensation of vapor. Therefore, to comprehend the mechanism that non-condensable gases affect condensation heat transfer is helpful to improve efficiency of heat transfer of devices.At the present work, the update development of experimental and theoretical researches about condensation heat transfer with non-condensable gases were present. These findings report effects of non-condensable gases on parameters, including condensation heat transfer coefficients, flow pattern and wall temperature. Meanwhile, variations of condensation heat transfer in the presence of non-condensable gases with various conditions, involving geometric conditions, flow pattern and species of non-condensable gases. By the contrast, the enhancement of heat transfer of condensation with non-condensable gases should give more concerns.

Abstract: The application of heat pump technology is one of the effective ways to realize energy conservation and emission reduction of air conditioning systems. In this paper a certain office building in Beijing is taken as an example, the annual cooling and heating load calculation is carried out. We select four cold and heat sources schemes to do comparative study, the four schemes are: air source heat pump, ground source heat pump, well water source heat pump and solar-ground coupled heat pump. The economy, characteristics and the impact on environment of each scheme are calculated and analyzed, and the Analytic Hierarchy Process (AHP) is used to comprehensively evaluate the four kinds of schemes. The results show that the comprehensive performance of well water source heat pump system is better than the other three schemes. Otherwise AHP provides a simple and practical method and basis for the heat and cold sources scheme selection and assessment.

Abstract: Heat transfer enhancement by pulsating flow in a triangular grooved channel has been experimentally investigated. Effects of Reynolds number Re, Strouhal number St, pulsation amplitude A on the heat transfer enhancement were studied. The experimental results show that, the pulsating flow can significantly enhance heat transfer compared to the steady flow case, for instance, an enhancement of 115% is achieved at Re=400, A=0.5 and St=0.3. There exists an optimal Strouhal number corresponding to the maximum heat transfer enhancement factor. The heat transfer enhancement factor increases with the increase of Reynolds number and pulsation amplitude.

Abstract: The cavitation in pump is an important factor impacts the operating safety of the pump, and against the cavitation occurrence, this paper chooses the SM253-640 centrifugal water pump as the study object to analysis the reason and the harm caused by cavitation. And this paper showed how to line-pump cavitation, especially, while the flow rate of the medium is very small and the temperature is high. The safety operating interval of the pump was analyzed in this paper, and showed how to avoid the pump cavitation and improve the pump working efficiency, to ensure the safety and economic operation of the heat supply network.Introduction

Abstract: The steady state distributed parameter model of heat exchangers in a heat-pump system was established in this paper. The calculating results of refrigerant quantities in the heat-exchangers show that refrigerant charge quantity in heating operating condition is less than that in refrigeration operating condition. Based on the differences of refrigerant mass flux between refrigeration and heating conditions, the exhaust bypass method to improve the operation efficiency of the heat-pump system was presented. And in order to prevent frosting on the surface of outdoor heat exchanger of the air source heat-pump, the solar energy assisted strategy was also applied in the heat-pump system.

Abstract: The leading structure of circumferential embedded high temperature heat-pipes in sidewall is considered as thermal protection system to prevent capsule type re-entry vehicle from the serious aerodynamic heating. It can lighten thermal load of windward and make good use of the endothermic capability of low temperature leeward. By means of fluid structure interaction method, we calculate the temperature distribution of capsule under given conditions and the maximum sidewall temperature decreases by 8.45%. The transfer of heat from windward to leeward is achieved, the windward of the thermal load is weakened and the ability of thermal protection is strengthened. The influence of structure parameters of heat-pipe-cooled capsule, flying attributes and materials attributes of coating to thermal protection effect are discussed in this paper to provide some references for the selection of leading structure and materials.

Abstract: natural draft counter flow cooling tower heat and mass transfer numerical simulation has been widely used to optimize the cooling tower design and to improve the thermal efficiency, but in published papers, a few important problems is not attracted attention, such as how does impact grid density to the calculation results; how does impact change of atmospheric density to the calculation results; drop diameter is an important parameter in numerical simulation, but it is not a exact experimental data, it is important to discuss how does impact drop size to the calculation results. This paper will explore and analyze these issues in the numerical simulation.

Abstract: The influences of alkaline earth metal salts (CaO, MgO) on the combustion property of pulverized coal have been studied by thermogravimetric analysis (TGA). It was indicated that CaO and MgO could improve combustion characteristics of pulverized coal. It was demonstrated that the catalysis of CaO and MgO to the pulverized coal combustion was embodied in the enhancement of the emission of volatile matters (VM) from pulverized coal, which reduced the ignition temperature. MgO exhibited remarkably higher catalytic activity than that of CaO for the combustion of fixed carbon. MgO catalytic combustion mechanism for pulverized coal was different from that of CaO.